Fuse contacts

ABSTRACT

An electrical contact for a cartridge fuse, the contact being stamped and formed from resilient sheet metal and comprising two superimposed strips forming a composite leg having a mounting foot at one end, in which the mounting foot has a surface facing generally away from the contact portion for engagement with an upper surface of a mounting board, and an axis of a cone of the contact converging with the plane in which the surface of the mounting foot is disposed at a location spaced from a side of the contact at which the end portions are located.

iinitet e States Dechelette 1 Mar. 18, 1975 1 FUSE CONTACTS [75]Inventor: Helen Dechelette, Saint Cloud,

France [73] Assignee: AMP Incorporated, Harrisburg, Pa.

[22] Filed: Nov. 29, 1973 [21] Appl. No.: 420,181

[30] Foreign Application Priority Data Dec. 14, 1972 France 72.44595[52] US. Cl. 339/256 C, 339/17 D, 339/52 R, 339/65, 339/150 F, 339/219F, 339/252 F,

[51] Int. Cl. ..1-ll051 1/04 [58] Field of Search... 339/17 R, 17 C, 17D, 50 R, 339/50 L, 50 S, 51, 52 R, 52 S, 56, 65, 66,

66 T, 93 R, 93 L, 95 R, 95 T, 119 L, 120,

125,150 F, 219 F, 252 F, 253 F, 256 R, 256

C, 258 R, 258 S, 258 P, 258 F, 262 R, 262 F,

[56] References Cited UNITED STATES PATENTS 2,338,835 l/l944 Bryant339/52 R 2,621,227 12/1952 McMahon 339/219 F 3,348,189 10/1967 Coldrenet a1. 339/32 R 3,360,765 l2/l967 Strange et a1. 339/50 R PrimaryExaminerRoy D. Frazier Assistant E.ramt'ner-Terre1l P. Lewis Attorney,Agent, or Firm-William J. Keating; Jay L. Seitchik; Frederick W. Raring[57] ABSTRACT An electrical contact for a cartridge fuse, the contactbeing stamped and formed from resilient sheet metal and comprising twosuperimposed strips forming a composite leg having a mounting foot atone end, in which the mounting foot has a surface facing generally awayfrom the contact portion for engagement with an upper surface of amounting board, and an axis of a cone of the contact converging with theplane in which the surface of the mounting foot is disposed at alocation spaced from a side of the contact at which the end portions arelocated.

4 Claims, 4 Drawing Figures FUSE CONTACTS This invention relates to acontact for a cartridge fuse having conical end caps formed fromelectrically conductive metal.

The present invention is a unitary electrical contact for a cartridgefuse having conical conductive ends, the contact being stamped andformed from resilient sheet metal and comprising two superposed stripsforming a composite leg having the mounting foot at one end, the stripsbeing bent apart at the other end and being integrally joined at theother end by a U channel receptacle having two spaced walls joined by abight, the channel extending generally along the axis of the compositeleg with the walls located in planes generally parallel to the plane ofthe composite leg, each channel wall being bent at an end portion remotefrom the bight away from the other wall into the form of a part surfaceof a cone the apex of which is located between the bight and the endportions and the axis of which extends from the apex away from the bightand between the channel walls, the two part-conical surfaces forming acontact portion.

An embodiment of the present invention will now be described, by way ofexample, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of two contacts according to the invention,a cartridge fuse and a printed circuit board prior to assembly of thevarious components;

FIG. 2 is a view looking in the direction of arrow A in FIG. 1, of oneof the contacts of- FIG. I mounted on the printed circuit board;

FIG. 3 is a view looking in the direction of the arrow B in FIG. 1 ofthe two contacts of FIG. I mounted on the printed circuit board prior tofull insertion ofa fuse; and

FIG. 4 is a view similar to FIG. 3 but showing the contacts after fullinsertion of the fuse.

Each contact is stamped from resilient sheet metal and then bent intothe form shown. A central portion comprises two superposed strips 11forming a composite leg 12. The strips 11 are bent apart at the upperend of the composite leg to form two halves ofa stop 13 the purpose ofwhich is explained below. The strips 11 are integrally joined at theupper end by a U channel receptacle 15 having two spaced walls 16 joinedby a bight 17, the channel extending generally along the axis of the leg12 with the walls 16 located in planes generally parallel to the planeof the leg 12. The free end portion 19 of each channel wall 16 is bentaway from the other wall at 20 into the form of a part surface of a conethe apex of which is located between the bight 17 and the free ends 19of the channel walls 16 and the axis 21 of which extends from the apexaway from the bight 17 and generally parallel to and between the walls16. The two part-conical surfaces 20 define together with the stop 13 acontact portion for receiving an end cap of a fuse as described below.The free ends 19 of the channel walls 16 are bent away from each otherat portions 22 remote from the leg 12 to form a flared mouth best seenin FIG. 2.

The strips 11 are bent apart at 23 the lower end of the leg 12 and areintegrally joined at the lower end by a U channel 24 generally alignedwith the receptacle 15. The channel 24 has a bight 25 joining two spacedwalls 26 which have free ends 27 projecting laterally beyond the leg 12.The free lower ends of the strips 11 are formed as spaced tabs 28extending in directions parallel to the leg 12.

To mount a pair of contacts 10 on a printed circuit board 29 two pairsof spaced through holes 30 are provided in the printed circuit board.Each contact 10 is applied to the upper surface 31 of the board 29 withits two tabs 28 received through respective holes 30 and with the loweredge 32 of the U channel 24 hard against the upper surface 31 as shownmost clearly in FIGS. 3 and 4. The tabs 28 are then bent upwardly andtowards each other against the lower surface 33 of the board as shown inFIG. 2 after which the tabs are soldered as shown at 34 to conductors onthe lower surface 33. As

shown in FIG. 3 the axes 21 about which the partconical surfaces 20 aregenerated converge between the two contacts 10 in a direction towardsthe board 29.. This is brought about because the lower edge 32 of the Uchannel 24 of each contact .10 is in a plane which converges with theaxis 21 of the associated part conical surfaces 20 at the side of thecontact at which the receptacle 15 opens into.

FIG. 1 shows a conventional form of cartridge fuse 35 which is formedwith an insulating body 36 and two conical conductive ends 37 joined.together by a fusible conductive strip 38.

Insertion of the fuse 35 into the receptacles 15 of the pair of contacts10 will now be described. The fuse 35 is inclined with one end 37 nearerthe board 28 than the other, and the one end 37 is introduced into areceptacle 15. In order to insert the other end 37 of the fuse 15 in theother contact 10, the other end 37 (the right-hand end as seen in FIG.3) is forced towards the board into the flared mouth of the receptacle15 of the right-hand contact 10, and the channel walls 16 flex apartallowing the other end 37 to snap into engagement with the part-conicalsurfaces 20 and the roof 13. As the other end 37 is being forced intoposition the receptacles 15 of the two contacts 10 are forced apart byflexure of each contact about the parts 23 and 13 joining the U channel24 and the receptacle 15, respectively, to the leg 12 to take up theposition shown in FIG. 4 on full insertion of the fuse 35. In thisposition the two conical axes 21 and the fuse axis are aligned parallelto the board 29. Thus the conical ends 37 are perfectly seated in therespective receptacles and the outward flexure of the contacts ensures astrong contact force and pull-out force.

In practice the receptacles may be manufactured in strip form andapplied by automatic insertion tooling to the printed circuit boards.

What is claimed is:

1. A unitary electrical contact for a cartridge fuse having conicalconductive ends, the contact being stamped and formed from resilientsheet metal and comprising two superposed strips having a contiguousportion forming a composite leg disposed in a first plane and having amounting foot at one end, the strips being bent apart at the other endand being integrally joined at the other end by a U channel receptaclehaving two spaced walls joined by a bight, the channel extendinggenerally along the axis of the composite leg with the walls located insecond and third planes generally parallel to the first plane, eachchannel wall being bent at an end portion remote from the bight awayfrom the other wall into the form of a part surface of a cone the apexof which is located between the bight and the end portions and the axisof which extends from the apex away from the bight and between thechannel walls, the two part-conical surfaces forming a contact portion.

2. A contact according to claim 1, in which the mounting foot has asurface disposed in a fourth plane perpendicular to the first plane, thesurface facing generally away from the contact portion for engagementwith the upper surface of a mounting board, and the axis of the coneconverges with the fourth plane in which the surface of the mountingfoot is disposed at a location spaced from a side of the contact atwhich the end portions are located.

joining two spaced walls which have free ends projecting laterallybeyond the composite leg, the free ends of the strips being formed asspaced tabs extending parallel to the composite leg.

1. A unitary electrical contact for a cartridge fuse having conicalconductive ends, the contact being stamped and formed from resilientsheet metal and comprising two superposed strips having a contiguousportion forming a composite leg disposed in a first plane and having amounting foot at one end, the strips being bent apart at the other endand being integrally joined at the other end by a U channel receptaclehaving two spaced walls joined by a bight, the channel extendinggenerally along the axis of the composite leg with the walls located insecond and third planes generally parallel to the first plane, eachchannel wall being bent at an end portion remote from the bight awayfrom the other wall into the form of a part surface of a cone the apexof which is located between the bight and the end portions and the axisof which extends from the apex away from the bight and between thechannel walls, the two part-conical surfaces forming a contact portion.2. A contact according to claim 1, in which the mounting foot has asurface disposed in a fourth plane perpendicular to the first plane, thesurface facing generally away from the contact portion for engagementwith the upper surface of a mounting board, and the axis of the coneconverges with the fourth plane in which the surface of the mountingfoot is disposed at a location spaced from a side of the contact atwhich the end portions are located.
 3. A contact according to claim 1,in which the end portions of the channel walls are bent away from eachother at portions remote from the leg to form a flared mouth.
 4. Acontact according to claim 1, in which the strips are bent apart at theone end by a U channel generally aligned with the receptacle, thechannel having a bight joining two spaced walls which have free endsprojecting laterally beyond the composite leg, the free ends of thestrips being formed as spaced tabs extending parallel to the compositeleg.